I bought once before and sold it. Expensive and even if it does make a difference.. you'd barely notice it. You can just polish the stock plunger with dremel. Browse youtube videos "25cents glock". I don't put any aftermarket internal parts in my Glocks except the 3lb connector.
Just my 2c.
I have one in my G31, its not something that you can tell a difference. They are just supposed to be tougher and last longer, i also have a titanium striker assembly. Same thing, you cant tell a difference but they are supposed to be tougher and last longer.
Semper paratus.....virtute et armis